Question: Simplify the following expression: $k = \dfrac{5yx}{2x^2 + 4yx} - \dfrac{2x^2 - 6yx}{2x^2 + 4yx}$ You can assume $x,y,z \neq 0$.
Answer: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{5yx - (2x^2 - 6yx)}{2x^2 + 4yx}$ $k = \dfrac{11yx - 2x^2}{2x^2 + 4yx}$ The numerator and denominator have a common factor of $x$, so we can simplify $k = \dfrac{11y - 2x}{2x + 4y}$